• Structural Engineering and Mechanics
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• v.69 no.4
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• pp.457-466
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• 2019

This paper presents an efficient higher-order nonlocal beam theory for the Critical buckling, of functionally graded (FG) nanobeams with porosities that may possibly occur inside the functionally graded materials (FG) during their fabrication, the nonlocal elastic behavior is described by the differential constitutive model of Eringen. The material properties of (FG) nanobeams with porosities are assumed to vary through the thickness according to a power law. The governing equations of the functionally graded nanobeams with porosities are derived by employing Hamilton's principle. Analytical solutions are presented for a simply supported FG nanobeam with porosities. The validity of this theory is studied by comparing some of the present results with other higher-order theories reported in the literature, Illustrative examples are given also to show the effects of porosity volume fraction, and thickness to length ratios on the critical buckling of the FG beams.

• Journal of Information Technology Applications and Management
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• v.25 no.4
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• pp.79-114
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• 2018

Although former scholarly studies mostly focus on exploring leadership effectiveness under the traditional hierarchical leader-subordinate relationship, the research of leadership performance for non-hierarchical organizational structures, particularly the mediating factors of higher-order goals, trust-in-leader, and self-efficacy have been ignored. This study, therefore, makes an attempt to ascertain the impacts of transformational leadership on the performance of subordinates through the mediating effects of higher-order goals, trust-in-leader, and self-efficacy and the differences of these effects in the context of multi-level marketing (MLM). Like the small-sample studies adopted by Barling, Weber, and Kelloway [1996], Barling, Slater, and Kelloway [2000] and Bass, Avolio, Jung, and Berson [2003], this study adopts a sample of 123 MLM distributors of an MLM company in Hong Kong, with a high response rate of 80.4%. The results indicate that the mediating effect of self-efficacy between transformational leadership and performance is significant under non-hierarchical organizational structures such as MLM in China.

• Steel and Composite Structures
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• v.45 no.3
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• pp.305-330
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• 2022

This article aims to investigate the static deflection and stress analysis of bi-directional functionally graded porous plate (BDFGPP) modeled by unified higher order kinematic theories to include the shear stress effects, which not be considered before. Different shear functions are described according to higher order models that satisfy the zero-shear influence at the top and bottom surfaces, and hence refrain from the need of shear correction factor. The material properties are graded through two spatial directions (i.e., thickness and length directions) according to the power law distribution. The porosities and voids inside the material constituent are described by different cosine functions. Hamilton's principle is implemented to derive the governing equilibrium equation of bi-directional FG porous plate structures. An efficient numerical differential integral quadrature method (DIQM) is exploited to solve the coupled variable coefficients partial differential equations of equilibrium. Problem validation and verification have been proven with previous prestigious work. Numerical results are illustrated to present the significant impacts of kinematic shear relations, gradation indices through thickness and length, porosity type, and boundary conditions on the static deflection and stress distribution of BDFGP plate. The proposed model is efficient in design and analysis of many applications used in nuclear, mechanical, aerospace, naval, dental, and medical fields.

• Bulletin of the Korean Mathematical Society
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• v.48 no.3
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• pp.627-636
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• 2011

In this paper, we obtain some applications of first order differential subordination and superordination results for higher-order derivatives of p-valent functions involving certain linear operator. Some of our results improve and generalize previously known results.

• Bulletin of the Korean Mathematical Society
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• v.46 no.4
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• pp.607-615
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• 2009

In this paper, we investigate the growth of solutions and the existence of subnormal solutions for a class of higher order linear differential equations. We obtain some results which improve and extend the results of Chen-Shon [2] and Gundersen-Steinbart [5].

• Bulletin of the Korean Mathematical Society
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• v.49 no.5
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• pp.911-921
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• 2012

In this paper, the radial oscillation of the solutions of higher order homogeneous linear differential equation $$f^{(k)}+A_{n-2}(z)f^{(k-2)}+{\cdots}+A_1(z)f^{\prime}+A_0(z)f=0$$ with transcendental entire function coefficients is studied. Results are obtained to extend some results in [Z. Wu and D. Sun, Angular distribution of solutions of higher order linear differential equations, J. Korean Math. Soc. 44 (2007), no. 6, 1329-1338].

• Journal of applied mathematics & informatics
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• v.32 no.3_4
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• pp.455-464
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• 2014

We establish some new criteria for the oscillation of mth order nonlinear difference equations. We study the case of strongly superlinear and the case of strongly sublinear equations subject to various conditions. We also present a sufficient condition for every solution to be asymptotic at ${\infty}$ to a factorial expression $(t)^{(m-1)}$.

• Journal of the Korean Statistical Society
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• v.25 no.3
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• pp.313-336
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• 1996

In this paper we consider weak convergence of some rescaled transi-tion probabilities of a real-valued, k-th order (k $\geq$ 1) stationary Markov chain. Under the assumption that the joint distribution of K + 1 consecutive variables belongs to the domain of attraction of a multivariate extreme value distribution, the paper gives a sufficient condition for the weak convergence and characterizes the limiting distribution via the multivariate extreme value distribution.

• Human Ecology Research
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• v.58 no.2
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• pp.131-148
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• 2020

This study examined the dual mediating effects of preschoolers' executive function and counterfactual thinking in the relationship between maternal reflective functioning and preschoolers' higher-order thinking. Participants included 293 preschoolers and their mothers in Daegu city and Gyeongsang province. The mothers completed questionnaires regarding their reflective functioning, preschoolers' executive function, and creative thinking. Teachers completed questionnaires regarding preschoolers' critical thinking and caring thinking. Preschoolers' counterfactual thinking was measured by interviews. Data were analyzed using descriptive statistics and Pearson correlation analysis with SPSS 25.0. Path analysis and bootstrapping were used with AMOS 25.0 program. Also, specific indirect effect were analyzed using AMOS user-defined estimand function. The primary results of this study are as follows. Maternal reflective functioning had an indirect effect on preschoolers' critical thinking and caring thinking through preschoolers' executive function and counterfactual thinking; however, maternal reflective functioning had no indirect effect on preschoolers' creative thinking through preschoolers' executive function and counterfactual thinking. This study revealed that maternal reflective functioning and preschoolers' executive function and counterfactual thinking need to be considered simultaneously to explain the level of preschoolers' higher-order thinking. The results highlight the dual mediating effects of preschoolers' executive function and counterfactual thinking in the relationship between maternal reflective functioning and preschoolers' higher-order thinking.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.38-44
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• 2010

In this paper, the higher order FDTD(Finite-Difference Time-Domain) method is used to obtain the frequency response characteristics of the cylindrical metamaterial slab. FDTD method is one of strongest electromagnetic numerical method which is widely used to analyze the metamaterial structure because of its simplicity and the dispersive FDTD equation which has the dispersive effective dielectric constant and permeability are derived to analyze the metamaterials. This derived dispersive FDTD equation has no errors in analyzing the dielectric materials but there are some time and frequency errors in case of analyzing the metamaterials. We used the higher order FDTD method to obtain the accurate frequency response of the metamaterials. Comparisons between the dispersive FDTD method and the higher order FDTD method are performed in this paper also. From the results, we concluded that more accurate frequency response for various metamaterials applications can be obtained using the proposed method in this paper.